The inventors have filed applications for ion sensors employing a carbon electrode (in which basal plane pyrolytic graphite carbon, namely BPG carbon, glassy carbon or the like is used as the electrically conductive carbon material) as a substrate, wherein the board is coated with a redox layer which may in turn be coated with an ion-selective layer.
With ion sensors so configured, however, there is a limitation upon the shape of the board and difficulties are encountered particularly in miniaturization and in utilizing the above-described art in circuit techniques involving semiconductors and the like.
In the future, sensor techniques employing ion sensors will not be limited to systems in which mere measurements are taken by using a sensor. Since there will be a need to develop software in the electronic, electrical, biological and fermentation fields and in the field of medicine (clinical medicine, diagnosis, examination, communication, etc.), it will be required to develop sensor technology in combination with sophisticated board technology.